22 research outputs found
A staggered fully explicit lagrangian Finite Element Method for Fluid-Structure-Interaction problems
Effectiveness of Virtual Reality Simulations for Civilian, Ab Initio Pilot Training
Aviation training in the immersive Virtual Reality (VR) world has the power to overcome physical constraints, presenting cues and stimuli that would not be available in flight, nor in a two-dimensional (2D) environment. This gives VR powerful potential as a simulation tool for learning complex skills and maneuvers in the cockpit. This study evaluated the effectiveness of VR simulations as compared to traditional 2D desktop simulations in teaching maneuvers and skills to ab initio (inexperienced) civilian pilot trainees. This quasi-experimental project involved 17 freshman pilot students in an experimental college course at a private university campus in the fall semester of 2020. The participants were split into two sections: Section 1 completed CBT activities and simulations in 2D only, while Section 2 completed CBT activities in 2D and simulations in VR. Academic performance data was collected in the Canvas Learning Management System, broken down by understanding of a maneuver learned in a given lesson module. Descriptive statistics collected included quizzes, discussion board activity, and simulation completion scores. Paired samples t-tests compared perceived benefits of using the various course materials. Researchers also administered post-semester surveys to gather both qualitative and quantitative data, in which participants shared their perceptions of the course, preference for learning material type, and general feedback. Results indicated that students in both groups found the sims/tutorials and VR to be enjoyable and gratifying; the majority of students indicated that simulations were preferred over other learning materials. Early results indicate that although the students perceived that the simulations were beneficial, there were no significant differences in the final course scores or learning rates between those who utilized 2D sims as opposed to VR sims. The most important finding is that for ab initio pilots, VR simulations do not hinder learning mastery, as compared with traditional 2D desktop simulations
A partitioned fully explicit Lagrangian finite element method for highly nonlinear fluid-structure interaction problems
In this work, a fully explicit partitioned method for the simulation of Fluid Structure Interaction (FSI) problems is presented. The fluid domain is modelled with an explicit Particle Finite Element Method (PFEM) based on the hypothesis of weak compressibility. The Lagrangian description of the fluid is particularly effective in the simulation of FSI problems with free surface flows and large structural displacements, since the fluid boundaries are automatically defined by the position of the mesh nodes. A distinctive feature of the proposed FSI strategy is that the solid domain is modelled using the explicit integration FEM in an off-the-shelf commercial software (Abaqus/Explicit). This allows to perform simulations with a complete and advanced description on the structural domain, including advanced structural material models and contact. The structure-to-fluid coupling algorithm is based on a technique derived from the Domain Decomposition Methods, namely, the Gravouil and Combescure algorithm. The method allows for arbitrarily large interface displacements using different time incrementation and nonconforming meshes in the different domains, which is an essential feature for the efficiency of an explicit solver involving different materials. The resulting fully explicit and fully lagrangian finite element approach is particularly appealing for the possibility of its efficient application in a large variety of highly non-linear engineering problems
RAC2 loss-of-function mutation in 2 siblings with characteristics of common variable immunodeficiency
Tributes to Daniel H. Teitelbaum, MD, PhD
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141090/1/jpen1079.pd